1. Field of the Invention
The present invention relates to an organic EL display panel, and more particularly, to an organic EL display panel which is suitable for a method for manufacturing an organic thin film or an electrode film such as a light emitting layer on a substrate by vapor deposition using a vapor deposition mask in a predetermined pattern. The present invention is also characterized by the structure of the vapor deposition mask for such vapor deposition.
2. Description of the Related Art
FIG. 15 is a schematic view of a method of manufacturing an organic EL display panel for explaining a method for forming an organic film such as a light emitting layer using a vapor deposition mask. In FIG. 15, a substrate 101 is a TFT substrate which constitutes an organic EL display panel. The substrate is usually formed of a glass plate. To a main surface (a surface on which an organic light emitting layer is formed) side of the substrate 101, a vapor deposition mask 102 having opening portions 103 is adhered by vapor deposition. The vapor deposition is performed by adhering a magnet plate 104 to a back surface (a surface opposite to the main surface) of the substrate 101 and by attracting the vapor deposition mask 102 which is made of magnetic metal.
In a state that the vapor deposition mask 102 is adhered to the substrate 101, a vapor-deposition particle flow which is vaporized from a vapor deposition source 105 is vapor-deposited to the substrate 101 through the opening portion 103 formed in the vapor deposition mask 102 thus forming a thin film layer 107 made of an organic material. Here, the thin film layer 107 is also formed on a surface of the vapor deposition mask 102 other than the opening portion 103.
However, it is difficult to completely adhere the vapor deposition mask 102 to the whole surface of the substrate 101 and hence, damages on the substrate 101 attributed to a contact of the substrate 101 with the vapor deposition mask 102 and the influence of foreign substances on the contact surface are large. These largely hamper the application of the mask vapor deposition to the mass production of OLED.
With respect to the formation of OLED film on the organic EL substrate by this type of mask deposition, Patent Document 1, Patent Document 2, Patent Document 3, Patent Document 4, Patent Document 5, Patent Document 6, Patent Document 7, and Patent Document 8 are named. In Patent Document 1, Patent Document 2, Patent Document 3 and Patent Document 4 disclose a method which performs the vapor deposition by adhering the substrate and the vapor deposition mask by a magnetic force. On the other hand, Patent Document 5, Patent Document 6, Patent Document 7 and Patent Document 8 disclose a method which reduces a contact area of the substrate and the vapor deposition mask by making a surface of the substrate or the vapor deposition mask rough by applying projections, ribs or irregularities to substrate or the vapor deposition mask thus decreasing damages on the substrate attributed to the contact of substrate and the vapor deposition mask.
Patent Document 1: JP-A-2004-146251
Patent Document 2: JP-A-2004-79349
Patent Document 3: JP-A-2002-47560
Patent Document 4: JP-A-2002-75638
Patent Document 5: JP-A-2004-71554
Patent Document 6: JP-A-2003-59671
Patent Document 7: JP-A-2003-213401
Patent Document 8: JP-A-2003-253434